Game balls are balls of a variety of shapes and sizes used to practice and play games. A baseball is a common game ball used by professionals and amateurs alike. Baseball professionals, especially pitchers, practice many years to throw baseballs with the desired flight path. Pitchers typically throw fast balls, curve balls, sliders, knuckleballs, and other pitches in attempts to prevent a batter from hitting the ball. Amateurs imitate these attempts, but frequently lack the training and experience necessary to throw these various pitches effectively.
Game balls having lightweight hollow spheres, usually made of plastic, have enabled less experienced players to throw professional style pitches. Fixed apertures have been added to slow the ball, and to vary the flight path. Some lightweight game balls have surface modifications to affect flight path. The surface modifications generally induce air resistance, causing drag, which results in the game ball deviating from a flight path it would have followed in the absence of the drag.
No known game ball has adjustable apertures, or combines adjustable apertures and surface modifications producing drag, to allow the user to throw a game ball with flight paths that vary to imitate professional pitches.